Hey.. The Navigation is okay and like someone said, it's like a Chinese unit. I would say it is a bit better than that but definitely not like Garmin etc. It works fine in metro cities though the touch system is not Capacitive and it takes a bit of effort to put in your address. The unit is a bit slow with respect to Camera and Navigation.
My opinion with respect to sound differs from the comment above. It is actually very good compared to other OEM units and surprisingly it works well on builtin standard speakers.
Bluetooth connectivity is okay too and streaming doesn't have much signal loss.
Been using it for over two and a half years, i don't have much complains..